This ice is as solid as at any time in the winter.

March 13. 

P. M. —To Flint’s Pond. 

Much warmer at last. 

On Flint’s Pond I cut a hole and measured the ice twenty-two rods from the shore nearest to Walden, where the water was nine feet deep (measuring from its surface in the hole). The ice was twenty-six inches thick, thirteen and one half of it being snow ice, and the ice rose above the water two inches. 

This ice is as solid as at any time in the winter. Three inches of snow above. 

It was so much work to cut this hole with a dull axe that I did not try any other place where it may have been thicker. Perhaps it was thicker in the middle, as in ’47.

H. D. Thoreau, Journal, March 13, 1856